One of the possible replacements for phosphate builders in synthetic detergent compositions is a water-insoluble metallo-silicate ion exchange material. Compositions containing such materials have been described in the published Dutch patent applications 74 03381, 74 03382 and 74 03383 filed by Henkel & Cie GmbH, and in the U.S. application Ser. Nos. 359,293 and 450,266 to Corkill et al.; 379,881 to Gedge et al.; 379,882 to Madison et al.; and 379,883 to Corkill et al.
Detergent compositions containing water-insoluble metallo-silicate ion exchange material tend to be less effective at high levels of water-hardness, particularly at levels above about 20.degree. H, in presence of appreciable amounts of water-soluble orthophosphates or pyrophosphates. Such appreciable amounts of lower water-soluble phosphates can, for example, result from polyphosphate hydrolysis (reversion) occurring during conventional spray-drying.
It is also known that the processing of detergent compositions containing the water-insoluble alumino-silicate builders is difficult, whereas the formed detergent granules tend to give raise to dust problems during storage resulting from a marginal abrasion resistance.
Accordingly, it is an object of this invention to formulate detergent compositions containing water-insoluble metallo-silicate ion exchange materials capable of providing superior washing and cleaning performance over a large range of washing conditions.
It is a further object of this invention to formulate granular detergent compositions containing metallo-silicate ion exchange materials which exhibit improved physical characteristics, particularly abrasion resistance.
It is yet another object of this invention to provide an improved spray-drying process for detergent compositions containing water-insoluble metallo-silicate builders.
It is a more specific object of this invention to provide a detergent composition containing a metallo-silicate ion exchange material and appreciable amounts of an auxiliary orthophosphate or pyrophosphate builder and the performance of which is substantially unaffected by the level of water-hardness.
The above and other objects are now met as will be seen from the following disclosure.